The subject matter disclosed herein relates to a method of determining the profile of a surface of an object using a video inspection device.
Video inspection devices, such as video endoscopes, can be used to inspect a surface of an object to identify and analyze defects on that surface that may have resulted from damage, wear, or improper manufacturing of the object. In many instances, the surface is inaccessible and cannot be viewed without the use of the video inspection device. For example, a video endoscope can be used to inspect the surface of a blade of a turbine engine on an aircraft to identify any defects (e.g., cracks) that may have formed on the surface to determine if any repair or further maintenance is required on that turbine engine. In order to make that assessment, it is often necessary to obtain highly accurate dimensional measurements of the surface and the defect to verify that the defect does not exceed or fall outside an operational limit or required specification for that object.
In order to determine the dimensions of a defect on a surface, a video inspection device can be used to obtain and display an image of the surface on an object showing the defect. This image of the surface can be used to generate three-dimensional data of the surface that provides the three-dimensional coordinates (e.g., (x, y, z)) of a plurality of points on the surface, including the defect. In certain measurement systems, if the angle of the video inspection device relative to the surface when the image was obtained is known, these three-dimensional coordinates of the points on the surface can then be used to determine the dimensions of the defect. For example, some measurement systems require that the video inspection device be perpendicular to the surface when capturing an image of the surface. However, in many instances, due to the fact that surface is inaccessible, it is difficult or impossible to orient the video inspection device to be perpendicular to the surface when capturing an image of the surface. In these instances, the measurement system cannot be used to determine the dimensions of the defect. In other instances where it is possible to orient the video inspection device to be perpendicular to the surface when capturing an image of the surface, it is often difficult or impossible to confirm that the image was taken when the video inspection device was exactly perpendicular. In these instances, the measurement system will provide inaccurate dimensions of the defect.
It would be advantageous to provide a method for determining the profile of a surface of an object, including any defect on that surface, in order to determine the dimensions of that defect, wherein the method does not require that the video inspection device be at a certain angle relative to the surface when an image of the surface is obtained (e.g., would allow non-perpendicular captures of the image).